UV-Crosslinkable Polyacrylate Adhesive Flagging Reduction

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Solution Overview

Problem

UV-crosslinked polyacrylate hot melt adhesives face challenges in achieving a stable balance between cohesion and adhesion, leading to a high tendency for flagging in adhesive tapes, especially when used for cable insulation and bundling, due to the narrow control range of cohesion-adhesion ratio and sensitivity to machine parameters and resin additions.

Innovation Solution

Incorporating terpene phenolic resins in a concentration of 2 to 4% by weight into the UV-crosslinkable polyacrylate hot melt adhesive composition, which improves the adhesive's flagging behavior by maintaining a balanced property profile and allowing compatibility with various carrier materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high crosslinking degree is achieved, then cohesion is improved, but flagging behavior worsens

Engineering Contradiction:
ImprovecohesionVSAvoidflagging behavior
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by controlling the UV dose and resin concentration to achieve an optimal crosslinking degree. This controlled approach ensures sufficient cohesion while preventing excessive crosslinking that would cause flagging, thereby resolving the contradiction between cohesion improvement and flagging prevention.

Inventive Principle:
Principle #35Parameter changes

2Strength

If UV dose is increased, then crosslinking is improved, but adhesion maximum stability worsens

Engineering Contradiction:
ImprovecohesionVSAvoidadhesion maximum stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by optimizing the UV dose within a specific range and using resin additives that broaden the process window. This approach allows the adhesive to maintain stable adhesion properties even with variations in UV dosing, thereby resolving the contradiction between crosslinking improvement and adhesion stability.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The addition of terpene phenolic resins significantly reduces the flagging tendency, enhancing adhesion and elasticity while maintaining sufficient shear life, allowing for stable performance over time and compatibility with diverse carriers.

Implementation Method 1

An important and frequently used process for crosslinking, in particular hot melt adhesives, is UV-initiated crosslinking

Methodology Applied
Scientific EffectUV-initiated crosslinking: Photopolymerisation

Implementation Method 2

Hot melt adhesives are becoming increasingly important in industrial bonding processes

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2806005B1UV-crosslinkable, resin modified adhesive mass
Publication Date: 2019.07.17 TESA SE
  • EP2806005B1 patent drawingFigure 1
  • EP2806005B1 patent drawingFigure 2~3
  • EP2806005B1 patent drawingFigure 4

AI summary

The tendency of a bond formed with a UV-curable adhesive to detach is to be reduced. This is achieved by providing a composition containing at least one UV-curable polyacrylate and at least one terpene phenolic resin, wherein the total concentration of the terpene phenolic resins, based on the total weight of the composition, is 1 to 5 wt.%. The invention further relates to an adhesive compound produced on the basis of this composition, an adhesive tape based thereon, and its use for sheathing elongated goods such as cable assemblies.